ESP32 DEVKIT in infinite loop, no serial connection

zgrate
Posts: 4
Joined: Tue Dec 03, 2019 6:25 pm

ESP32 DEVKIT in infinite loop, no serial connection

Postby zgrate » Tue Dec 03, 2019 6:29 pm

Hello
One day, after flashing software on my ESP32, it only dimmed the light down and disconnected from PC. Now, when I connect to PC (using different USB cables) the LED light up only a little bit, and the PC don't recognise the board. Only when I hold EN it is detected, but I can't flash new software using this method.
Is there any solution for this or the board is dead?

ESP_Sprite
Posts: 2914
Joined: Thu Nov 26, 2015 4:08 am

Re: ESP32 DEVKIT in infinite loop, no serial connection

Postby ESP_Sprite » Wed Dec 04, 2019 2:42 am

What devkit specifically do you have? Are you sure there's nothing wrong with the power supply or USB cable, or anything shorted?

zgrate
Posts: 4
Joined: Tue Dec 03, 2019 6:25 pm

Re: ESP32 DEVKIT in infinite loop, no serial connection

Postby zgrate » Wed Dec 04, 2019 7:57 am

DOIT ESP 32 DEVKIT V1

What pins should I check internally for shorts?
The power consumption (measured by USB charger doctor) is steadly on 0.02A during faulty boot, on holding ENABLE it drops to 0.00A (out of the range of the charger)

ESP_Sprite
Posts: 2914
Joined: Thu Nov 26, 2015 4:08 am

Re: ESP32 DEVKIT in infinite loop, no serial connection

Postby ESP_Sprite » Wed Dec 04, 2019 11:10 am

Can you measure the 3.3V line on the board, see if that is drooping?

zgrate
Posts: 4
Joined: Tue Dec 03, 2019 6:25 pm

Re: ESP32 DEVKIT in infinite loop, no serial connection

Postby zgrate » Wed Dec 04, 2019 2:43 pm

Oh, it's 1.4V or 1.8V with ENABLE, so here is the problem
Should I check all pins or start with specific one?

ESP_Sprite
Posts: 2914
Joined: Thu Nov 26, 2015 4:08 am

Re: ESP32 DEVKIT in infinite loop, no serial connection

Postby ESP_Sprite » Thu Dec 05, 2019 1:17 am

I think your LDO (the chip that generates 3.3V from 5V) might be broken in that case. Hard to say how that ended up happening, but you may be able to double-check by manually applying 3.3V to the board if you have a lab psu or something.

zgrate
Posts: 4
Joined: Tue Dec 03, 2019 6:25 pm

Re: ESP32 DEVKIT in infinite loop, no serial connection

Postby zgrate » Thu Dec 05, 2019 1:31 pm

Yep, problem solved. When I plugged in 3.3v external power, everything works. I've bought new regulator and will plug it as a replacement.
Thank you, topic to close

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